Method of making bullets



Aug. 11, 1959 G. E. FROST METHOD OF MAKING BULLETS ori inal Filed March 5, 1952 Fig.4

INVENTOR. Gecrge E. F rost- Cid/aw.

AGENT United States P fi O p METHOD OF MAKING BULLETS George E. Frost, Hamden, Conn., assignor to Olin vided and this application November 1, 1955, Serial No. 547,880

8 Claims. (Cl. 29-122) This invention relates generally to ammunition and more particularly to compound projectiles and to a method for making improved projectiles of this type. This application is a division of my c o-pending application, Serial No. 274,870, filed March 5, 1952, now Patent No. 2,751,845, and the product set forth herein is described and claimed in said co-pending application.

Ammunition projectiles are ordinarily composed of a metal core and a harder metal jacket. These projectiles are usually referred to as compound projectiles and have replaced most of the lead slugs formerly utilized as projectiles because of the relatively poor accuracy of the soft lead slug due to excessive deformation of the surface thereof by the riding in the gun barrel. The soft metal core of compound projectiles is protected from this deformation'by the harder metal jacket which substantially completely encloses those portions adjacent the barrel rifling. In this type of projectile, the nose or tip of the bullet is formed from the core metal and the jacket is normally referred to as a base jacket. In still another type of compound projectile, a second jacket often called a tip jacket is utilized in conjunction with the base jacket to completely enclose the softer core.

Since the advent of the compound projectile, it has been recognized that the effectiveness thereof is impaired if the base jacket and core separate when the projectile strikes the target. When the jacket separates from the score upon impact with the objective, there is a loss in penetrating power and destructive action. Consequently, many methods for securing or locking the core to the base jacket have been proposed. One of the earlier suggestions is disclosed in US. Patent 680,549, issued to Smith, August 13, 1901. Smith perforated the jacket wall covering the base or rear end of the core and drove or otherwise forced the jagged prongs of metal formed in making the perforation into the core. It was found in practice, however, that the prongs of metal break and that this type of lock does not prevent separation of the core from the jacket when the projectile strikes the target. Probably the most common practice heretofore hasbeen to embed a portion of the jacket wall in the core metal by forming one or more circumferential rings or similar indentations therein after the core has been consolidated within the jacket. Indentations of this type which are formed after the core and jacket have been assembled taper to smaller dimensions within the core than adjacent the jacket wall and cannot be forced to a very great depth into the core without excessive thinning of the jacket metal. As a result, such indentations do not securely lock the core and base jacket together and the core frequently moves relative to the jacket when the target is struck by the projectile.

It is therefore an object of this invention to provide an improved compound projectile. It is another object of this invention to provide a novel lock between the base jacket and core of compound projectiles. A further object of this invention is to provide a novel method for making a compound projectile. A still further object is 2,898,666 Patented Aug. 11, 1959 2 V to provide a projectile having the core and jacket thereof securely locked against relative movement.

Other objects and advantages will become apparent from the following detail description and accompanying drawing, in which,

Figures 1, 2, and 3 are vertical views of base jacket and punch assemblies illustrating successive steps in a process embodying this invention, and

Figure 4 is a vertical view partly in section-of a projectile illustrating an embodiment of this invention.

In accordance with this invention, the foregoing objects as well as others are accomplished, generally speaking, by providing a compound projectile having the core secured to the jacket thereof by means of a protuberance integral with the jacket wall; the protuberance having a shoulder or portion of greater dimension adjacent the end embedded in the core. It has been found that the metal slug utilized as the core of a compound projectile can be forced about the periphery of a protuberance of this type and into a position substantially contiguous with the inner surface of the jacket by means of the conven tional pressing operation utilized heretofore to consolidate the core within the jacket. In accordance with this invention, the jacket is locked to the core by indenting the jacket wall, shaping the indented metal to form such a knob-like protuberance and then assembling the core and jacket.

Referring now to the drawing fora more detailed description of one embodiment of this invention, Figure 1 illustrates a conventional gilding metal base jacket 1 with a cylindrical boss 3 formed in the end thereof. In forming this boss, jacket 1 is inserted in a conventional core and jacket assembly die with the end or base thereof resting on punch 5. Punch 2 having a cavity6 in the end thereof is inserted in jacket 1 against the inner surface of the jacket wall, and punch 4 is moved upward and the area of the jacket wall between punch 4 and cavity 6 of punch 2 is cold worked to form boss 3.

As shown in Figure 2, punches 4 and 5 are retained in the positions shown in Figure 1 but punch 2 is Withdrawn and a semi-spherical ended punch 7 is inserted in jacket 1. The wall forming the closed end of boss 3 is then compressed between punch 7 and punch 4 which cold work the metal in the unconfined end of boss 3 and force it to flow at right angles to the direction of the applied pressure to form a flange or shoulder 8 around the periphery of boss 3 and convert it into a rounded protuberance resembling a knob 11 comprising a flange 8 and a cylindrical stem 12.

After the formation of the knob 11 from boss 3 as shown in Figure 2, punch 7 is withdrawn and a lead slug 10 is inserted in jacket 1 and pressed by means of a punch 9 to consolidate it within jacket 1 and about the periphery of knob 11 as shown in Figure 3. The assembly of jacket 1 and core 10 are then formed into a compound projectile such as shown in Figure 4 with conventional tools designed to impart the desired profile thereto.

Unlike most projectiles of the prior art, the jacket and core of the projectile of this invention are securely locked and separation thereof upon impact with an objective is prevented by the knob-like protuberance 11. The shoulder of the protuberance provides a lock between the core and jacket which is much stronger than the lock provided by the rather shallow indentations in the jacket wall heretofore utilized in compound projectiles. Due to this shoulder embedded in the core, shearing of the core metal and separation from the jacket is prevented.

While in the foregoing specific embodiment a gilding metal jacket and a lead core are assembled to form a projectile, other suitable metals can be utilized for making these component parts. For instance, soft lead alloys containing minor quantities of antimony or arsenic .can be utilized to advantage for the core of some projectiles and the jacket can be made from various copper base alloys, aluminum or iron. Likewise, instead of ,,forming a cylindrical boss in the firststep of the process, apolygonale, triangular- .or irregular-shaped indentation can be formed in the jacketwall and the knob-like protuberance thus need not be rounded.

In addition to the foregoing suggested modifications in the embodiment described in .detail herein, other modifications can be made without departing from the spirit or scope .of this invention. This invention is particularly useful in the type of projectile illustrated in Figure 4 and can be utilized to advantage in making other types ofmushrooming and other compound projectiles.

Having thus described this invention what is claimed is:

1, In the manufacture of jacketed projectiles, the proc ess for securing the jacket to the core thereof which comprises indenting the jacket wall until an internal protuberance thereof is formed therein, compressing the end of said protuberance until a knob-like portion is formed thereon, inserting the .core material in said jacket, and compressing the assembly until the core material has filled the space about said knob-like portion and the projectile has the desired shape.

2. In the manufacture of projectiles, the process which comprises forming in a jacket wall an internal protuberance having a relatively small basal end adjacent the jacket wall and a distal end of greater cross sectional di mension spaced from said wall, pressing a core into the jacket about said protuberance and pressing to the desired shape. v

3. In the manufacture of jacketed projectiles, the process which comprises forming an internal boss in the jacket wall, cold working the closed end of said 'boss to form a knob-like protuberance, and pressing a core about said protuberance.

4. In the manufacture of projectiles, the process for securing the jacket to the core thereof which comprises forming a cylindrical boss in the jacket wall, forming on said boss a knob-like protuberance by cold working 4 r a said boss, and pressing the core about said protuberance. 5. In the manufacture of projectiles, the process for securing the jacket to the core thereof which comprises forming a boss in the jacket wall, forming a knob-like protuberance on the closed end of said boss by cold working said closed end, and pressing the core about said protuberance.

v6. In the manufacture of jacketed projectiles, the process for securing the jacket to the core thereof which comprises indenting the jacket wall until an internal protuberance thereof is formed therein, compressing the end of said protuberance until a knob-like portion is formed thereon, inserting the core material in said jacket, and.

ess which comprises forming in a wall of said jacket a protuberance having a head joined to said wall by a stem of smaller cross section than said head, and pressing a core into the jacket and about said protuberance to lock said core in said jacket.

References Cited in the file of this patent UNITED STATES PATENTS Great Britain Oct. 11, 1 940 

